There are many applications in which is desirable or necessary to obtain a measurement of the concentration of a chemical component (e.g., hydrogen peroxide) in a fluid, including, but not limited to, a liquid and vapor sterilization system. Several techniques have been developed in the prior art to measure the concentration of hydrogen peroxide (H2O2) in a fluid. These techniques include the use of electrochemical sensors (e.g., an amperometric electrode coated with a hydrophilic or hydrophobic membrane), infrared sensors, color indicators, radio-frequency systems, gas analyzers, and spectroscopy (e.g., photometric infrared).
The dielectric constant (K) of a dielectric material is related to the permittivity (ε) of the dielectric material by the relationship K=ε/ε0, where ε0 is the permittivity of free space. In accordance with this relationship, changes to the permittivity (ε) of the dielectric material result in changes to the dielectric constant (K) of the dielectric material.
The present invention provides a method and apparatus for determining chemical concentrations using changes in the permittivity and dielectric constant of a dielectric material.